Which drug inhibits Na+-K+ ATPase pump –
**Core Concept**
The Na+-K+ ATPase pump, also known as the sodium-potassium pump, is a crucial enzyme that maintains the resting potential of neurons and other excitable cells by pumping sodium ions out of the cell and potassium ions into the cell. This pump requires energy from ATP hydrolysis to function.
**Why the Correct Answer is Right**
The correct answer is a drug that specifically inhibits the Na+-K+ ATPase pump, leading to an accumulation of sodium ions inside the cell and an efflux of potassium ions. This results in a depolarization of the cell membrane, which can lead to a range of clinical effects, including muscle weakness, cardiac arrhythmias, and seizures. Digitalis glycosides, such as digoxin, bind to the Na+-K+ ATPase pump and inhibit its activity, leading to an increase in intracellular sodium and a decrease in intracellular potassium.
**Why Each Wrong Option is Incorrect**
**Option A:** This is a beta-blocker, which works by inhibiting the beta-adrenergic receptors in the heart, reducing heart rate and contractility.
**Option B:** This is a calcium channel blocker, which works by inhibiting the influx of calcium ions into cardiac and smooth muscle cells, leading to vasodilation and a decrease in blood pressure.
**Option C:** This is an ACE inhibitor, which works by blocking the conversion of angiotensin I to angiotensin II, leading to vasodilation and a decrease in blood pressure.
**Clinical Pearl / High-Yield Fact**
Digitalis toxicity can be treated with potassium supplements, as potassium helps to restore the balance of sodium and potassium ions in the cell.
**Correct Answer: D. Digoxin**